The present application relates to systems and methods for performing surgery in a patient, and more particularly but not exclusively relates to systems, devices and techniques for facet joint stabilization and/or fusion.
The human spine serves many functions. The vertebral members of the spinal column protect the spinal cord. The spinal column also supports other portions of the human body. Additionally, moveable facet joints and resilient discs disposed between the vertebral members permit motion between individual vertebral members. Each vertebra includes an anterior body and a posterior arch. The posterior arch includes two pedicles and two laminae that join together to form the spinous process. A transverse process is laterally positioned at the transition from the pedicles to the laminae. Both the spinous process and transverse process provide for attachment of fibrous tissue including, for example, muscle. Two inferior articular processes extend downward from the junction of the laminae and the transverse process. Further, two superior articular processes extend upward from the junction. The articular processes of adjacent vertebrae form the facet joints. The inferior articular process of one vertebra articulates with the superior articular process of the adjacent vertebra. The facet joints may be considered to constitute gliding joints because the articular surfaces glide over one another.
Vertebral implants are often used in the surgical treatment of spinal disorders such as degenerative disc disease, disc herniations, curvature abnormalities, and trauma. Many different types of treatments are used. In some cases, spinal fusion is indicated to inhibit relative motion between vertebral bodies. Spinal fusion often involves the removal of at least a portion of the vertebral disc and insertion of an interbody implant to create a fused junction between a pair of vertebral bodies. These techniques may also involve the implantation of stabilization members such as, for example, rods or plates, outside of the disc space. In addition to or in lieu of fusion of the adjacent vertebrae across the disc space, the facet joints may be stabilized and/or fused to alleviate pain or discomfort. In comparison to the disc space between adjacent vertebrae, the space between the superior and inferior articular processes at the facet joint is relatively small, thereby leading to difficulties in accessing and positioning an implant within the space. Moreover, the anatomy and size of the space between the superior and inferior articular processes at the facet joints can limit the amount of bone growth promoting materials or grafts that can be positioned therebetween and/or result in the expulsion of at least some of the bone growth promoting materials therefrom. These and other factors may result in pseudarthrosis or inadequate stabilization or fusion of the facet joint. Thus, there remains a need for further improvements in the devices, instruments, assemblies, apparatuses, systems, and methods for performing facet joint stabilization and/or fusion techniques.